WINNIPEG--For the second time in three weeks, Mike Mintenko of Moose Jaw, Sask., broke the Canadian record in the men's 100-metre butterfly Thursday at the Sears I Can Swim Summer National Championships 2000 swimming competition.

The Vancouver-based Mintenko went under 53 seconds for the first time in his career clocking 52.88 in his semifinal heat. It was the 10th fastest time in the world this year. He'll have an opportunity to lower it again Friday in the final. His previous national standard was set in Los Angeles on July 16 at 53.10.

&QUOT;This is a world class time and that's what I've been shooting for,&QUOT; said Mintenko, 25, a double World Cup champion on the short course circuit this past winter. &QUOT;I'm on a roll right now and my confidence is high. I want to solidify this performance by going even faster tomorrow night in the final. There's plenty of time to take it down even more for the Olympics.&QUOT;

Two more Canadian records were broken in non-Olympic events: in the women's 50 breaststroke, Rhiannon Leier of Winnipeg clocked 32.31 in the preliminaries to eclipse the 32.48 held by Keltie Duggan of Calgary since 1993. Then she swam 32.18 for second spot in the final. World record holder Penny Heyns of South Africa, who trains in Calgary, won gold in 31.52.

In the men's 50 breaststroke, Morgan Knabe of Edmonton swam 28.77 in the semifinal to beat his Canadian standard of 28.85 set this past January. He won the final in 28.88.

The competition also serves as the final qualifying meet for the 2000 Olympic Games next month. Thirty-six swimmers qualified at the Olympic trials in June. No new names were added to the team Thursday.

Other winners in men's competition were Curtis Myden of Calgary in the 400 individual medley for his 27th career national title, Mark Johnston of St. Catharines, Ont., in the 200 freestyle; and Mark Versfeld of Vancouver in the 50 backstroke.

Other women victors were Liz Warden of Toronto in the 400 IM and Jennifer Button of Waterloo, Ont., in a personal best 2:11.64 in the 200 butterfly.